The invention relates generally to power generation systems, and more particularly to hybrid solar power generation systems.
Concentrated solar power (CSP) is currently considered the most economic and efficient way of generating electricity from solar energy at large scale. However, there are still significant challenges, beside the high capital cost of solar collection system, that limit the wide adoption of CSP technology for large-scale power generation. One such challenge with the current generation of solar power plants is the low production capacity factor due to the intermittent nature of solar energy. This intermittent nature of solar energy results in the CSP plants costly steam turbine cycle systems being idle as much as 75% of the time. The low utilization of the power island results in a very low return on investment (ROI) of the power system and, therefore, negatively impacts the economics of the CSP plant.
Another challenge with current generation of solar power plants is that the addition of large amounts of renewable power into the grid often necessitates the addition of natural gas based backup or reserve capacity in order to offset the intermittent nature of renewable energy and provide stability to the grid. From the perspective of grid operators and consumers, this redundancy in capacity is another hidden source of high cost of electricity as a result of adding more renewable power to the grid. Such reserve power plants typically operate at low capacity factors and use only simple cycle gas turbines that have lower efficiency and, therefore, emit more CO2 per MWh than combined cycle gas turbine (CCGT) plants. To circumvent the low capacity factor of the concentrated solar power, molten salt based thermal storage technologies have been proposed and demonstrated at small scale; however, these systems require additional technology development prior to use on a large scale to overcome the high initial capital costs and the low thermal efficiencies due to the use of indirect heat transfer and steam turbine cycles.
With respect to the solar reformer, designs for small-scale solar reforming, which is aimed at hydrogen production via ultra high temperature steam methane reforming has been attempted. Although possibly acceptable for small scale applications, this design is not suitable for power generation scenarios due to the high cost of solar thermal heating systems and high consumption of water.
It would therefore be desirable to provide an improved hybrid solar power generation system that corrects the above issues related to large-scale concentrated solar power generation.